1. Technical Field
The present invention generally relates to a phase controller and, more particularly, to a phase controller capable of driving a plurality of bridge circuits and a multi-phase voltage converter using the phase controller.
2. Description of Related Art
With the development of power management technology, DC-to-DC voltage converters have become widely used. Generally, DC-to-DC voltage converters are divided into three categories: boost converters, buck converters and buck-boost converters. A boost converter is capable of increasing the input voltage. On the contrary, a buck converter is capable of decreasing the input voltage. A buck-boost converter is capable of stepping up or down the input voltage. Among them, buck converters are more popular.
A multi-phase voltage converter includes a plurality of converter modules therein and uses the converter modules to process a single input voltage. More specifically, each of the converter modules usually includes an upper bridge switch and a lower bridge switch. A central controller of the multi-phase voltage converter controls the duty cycles of the upper bridge switch and the lower bridge switch such that the converter modules alternately provide an output voltage according to the input voltage.
However, the conventional multi-phase voltage converter has some drawbacks. More specifically, the conventional multi-phase voltage converter uses only one of the converter modules each time to provide the output voltage. In other words, the converter modules fail to provide power at the same time. When the back-end circuit is overloaded, the conventional multi-phase voltage converter that uses only one of the converter modules to provide the output voltage fails to provide the back-end circuit with sufficient power. For a two-phase DC-to-DC voltage converter, the maximum duty cycle of each converter module is 50%. Moreover, there is hardware limitation on the internal logic control circuit of the central controller that prevents the converter modules from providing power at the same time.